Encoder systems typically include a signal-generating (e.g., light-generating) emitter, a sensor (e.g., optical sensor) that receives signals from the signal-generating emitter, and a rotating disc disposed between the signal-generating emitter and the sensor. The disc includes a plurality of openings through which the signals from the signal generating emitter pass to the sensor. By measuring the signals received through the rotating disc, it is possible to determine a rotational angular position, direction of rotation, as well as speed, of the rotating disc.